Automated slide preparation systems for analyzing biological materials are known in the art. For example, U.S. Pat. Nos. 5,143,627, 5,282,978, and 6,562,299, and U.S. Patent Application Publication Nos. 2003-0207455 A1 and 2003-0207456 A1, all of which are incorporated herein by reference in their entirety, describe such automated systems. Some or all of these slide preparation systems employ a collection vessel having a filter that is introduced into the sample liquid and onto which a selected quantity of the dispersed sample of cells are collected. A pressure system connected with the collection vessel draws sample liquid into the vessel for collecting the cells on the filter surface.
In automated slide preparation systems, it is often desired that the biological sample, from which cells are obtained, be agitated prior to cell collection. Agitation of the sample causes cell clusters, bits of tissue, and mucous to break up and create a relatively homogenous sample of cellular material. Some automated slide preparation systems agitate the biological sample by immersing the vessel having the filter into the biological sample and rotating the vessel at high speeds. The high speed rotation causes the biological sample solution to rotate as well, which causes the necessary agitation and mixing of the solutions. However, the high speed rotation also causes small amounts of the mixture to aerosolize or splash out of the vial containing the biological sample, thereby increasing the chances of cross-contamination.